New release of {knitr} is causing tests to fail

[zkamvar]

Let this be a lesson to you kids about writing tests based on expectations of messages from other packages.

Consider this test:

sandpaper/tests/testthat/test-build_lesson.R

Lines 7 to 15 in 6211631

	test_that("Lessons built for the first time are noisy", {
	skip_if_not(rmarkdown::pandoc_available("2.11"))
	# It's noisy at first
	suppressMessages({
	expect_output(build_lesson(tmp, preview = FALSE, quiet = FALSE),
	"ordinary text without R code")
	})

We expect knitr to produce output that says "ordinary text without R code" like this:

> knitr::knit(text = "hello there!\n\n```{r rversion}\nR.version.string\n```\n") |> writeLines
  ()                                                                                          
  |............................                                                        |  33%
  ordinary text without R code

  |........................................................                            |  67%
label: rversion
  |....................................................................................| 100%
  ordinary text without R code


hello there!


```r
R.version.string
```

```
## [1] "R version 4.2.2 Patched (2022-11-10 r83330)"
```

Well.... I should have really paid attention because this progress bar has been a thorn in Hadley's craw for a WHILE: yihui/knitr#1880

With {knitr} version 1.42, the printing is now completely changed:

> knitr::knit(text = "hello there!\n\n```{r rversion}\nR.version.string\n```\n") |> writeLines
  ()                                                                                         
  |                                                                         |   0%
  |........................                                                 |  33%           
  |.................................................                        |  67% (rversion)                                                                               
  |.........................................................................| 100%           
                                                                                                                                                                

hello there!


```r
R.version.string
```

```
## [1] "R version 4.2.2 Patched (2022-11-10 r83330)"
```

Which means that, while there is output, it's no longer the output we expect and thus it breaks our tests 😢

[zkamvar]

The good thing is that I now have a pathway to improve the progress bars if I wanted to